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/*

 * Copyright (C) 2001-2004 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include <typedefs.h>

#include <arch/types.h>

#include <mm/heap.h>

#include <mm/frame.h>

#include <mm/vm.h>

#include <panic.h>

#include <debug.h>

#include <list.h>

#include <synch/spinlock.h>

#include <arch/asm.h>

#include <arch.h>

spinlock_t zone_head_lock;       /**< this lock protects zone_head list */

link_t zone_head;                /**< list of all zones in the system */

static struct buddy_system_operations  zone_buddy_system_operations = {

    .find_buddy = zone_buddy_find_buddy,

    .bisect = zone_buddy_bisect,

    .coalesce = zone_buddy_coalesce,

    .set_order = zone_buddy_set_order,

    .get_order = zone_buddy_get_order,

};

/** Initialize physical memory management

 *

 * Initialize physical memory managemnt.

 */

void frame_init(void)

{

    if (config.cpu_active == 1) {

        zone_init();

    }

    frame_arch_init();

    if (config.cpu_active == 1) {

                frame_region_not_free(config.base, config.base + config.kernel_size + CONFIG_STACK_SIZE);

        }  

}

/** Allocate a frame

 *

 * Allocate a frame of physical memory.

 *

 * @param flags Flags for host zone selection and address processing.

 *

 * @return Allocated frame.

 */

__address frame_alloc(int flags)

{

    ipl_t ipl;

    link_t *cur, *tmp;

    zone_t *z;

    zone_t *zone = NULL;

    frame_t *frame = NULL;

    __address v;

loop:

    ipl = interrupts_disable();

    spinlock_lock(&zone_head_lock);

    /*

     * First, find suitable frame zone.

     */

    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {

        z = list_get_instance(cur, zone_t, link);

        spinlock_lock(&z->lock);

        /*

         * Check if the zone has any free frames.

         */

        if (z->free_count) {

            zone = z;

            break;

        }

        spinlock_unlock(&z->lock);

    }

    if (!zone) {

        if (flags & FRAME_PANIC)

            panic("Can't allocate frame.\n");

        /*

         * TODO: Sleep until frames are available again.

         */

        spinlock_unlock(&zone_head_lock);

        interrupts_restore(ipl);

        panic("Sleep not implemented.\n");

        goto loop;

    }

    tmp = zone->free_head.next;

    frame = list_get_instance(tmp, frame_t, link);

    frame->refcount++;

    list_remove(tmp);           /* remove frame from free_head */

    zone->free_count--;

    zone->busy_count++;

    //v = zone->base + (frame - zone->frames) * FRAME_SIZE;

    v = FRAME2ADDR(zone, frame);

    if (flags & FRAME_KA)

        v = PA2KA(v);

    spinlock_unlock(&zone->lock);

    spinlock_unlock(&zone_head_lock);

    interrupts_restore(ipl);

    return v;

}

/** Free a frame.

 *

 * Find respective frame structrue for supplied addr.

 * Decrement frame reference count.

 * If it drops to zero, move the frame structure to free list.

 *

 * @param addr Address of the frame to be freed. It must be a multiple of FRAME_SIZE.

 */

void frame_free(__address addr)

{

    ipl_t ipl;

    link_t *cur;

    zone_t *z;

    zone_t *zone = NULL;

    frame_t *frame;

    ASSERT(addr % FRAME_SIZE == 0);

    ipl = interrupts_disable();

    spinlock_lock(&zone_head_lock);

    /*

     * First, find host frame zone for addr.

     */

    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {

        z = list_get_instance(cur, zone_t, link);

        spinlock_lock(&z->lock);

        if (IS_KA(addr))

            addr = KA2PA(addr);

        /*

         * Check if addr belongs to z.

         */

        if ((addr >= z->base) && (addr <= z->base + (z->free_count + z->busy_count) * FRAME_SIZE)) {

            zone = z;

            break;

        }

        spinlock_unlock(&z->lock);

    }

    ASSERT(zone != NULL);

    frame = ADDR2FRAME(zone, addr);

    // frame = &zone->frames[(addr - zone->base)/FRAME_SIZE];

    ASSERT(frame->refcount);

    if (!--frame->refcount) {

        list_append(&frame->link, &zone->free_head);    /* append frame to free_head */

        zone->free_count++;

        zone->busy_count--;

    }

    spinlock_unlock(&zone->lock);  

    spinlock_unlock(&zone_head_lock);

    interrupts_restore(ipl);

}

/** Mark frame not free.

 *

 * Find respective frame structrue for supplied addr.

 * Increment frame reference count and remove the frame structure from free list.

 *

 * @param addr Address of the frame to be marked. It must be a multiple of FRAME_SIZE.

 */

void frame_not_free(__address addr)

{

    ipl_t ipl;

    link_t *cur;

    zone_t *z;

    zone_t *zone = NULL;

    frame_t *frame;

    ASSERT(addr % FRAME_SIZE == 0);

    ipl = interrupts_disable();

    spinlock_lock(&zone_head_lock);

    /*

     * First, find host frame zone for addr.

     */

    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {

        z = list_get_instance(cur, zone_t, link);

        spinlock_lock(&z->lock);

        if (IS_KA(addr))

            addr = KA2PA(addr);

        /*

         * Check if addr belongs to z.

         */

        if ((addr >= z->base) && (addr <= z->base + (z->free_count + z->busy_count) * FRAME_SIZE)) {

            zone = z;

            break;

        }

        spinlock_unlock(&z->lock);

    }

    ASSERT(zone != NULL);

    //frame = &zone->frames[(addr - zone->base)/FRAME_SIZE];

    frame = ADDR2FRAME(zone, addr);

    if (!frame->refcount) {

        frame->refcount++;

        list_remove(&frame->link);          /* remove frame from free_head */

        zone->free_count--;

        zone->busy_count++;

    }

    spinlock_unlock(&zone->lock);  

    spinlock_unlock(&zone_head_lock);

    interrupts_restore(ipl);

}

/** Mark frame region not free.

 *

 * Mark frame region not free.

 *

 * @param start First address.

 * @param stop Last address.

 */

void frame_region_not_free(__address start, __address stop)

{

        __address a;

        start /= FRAME_SIZE;

        stop /= FRAME_SIZE;

        for (a = start; a <= stop; a++)

                frame_not_free(a * FRAME_SIZE);

}

/** Initialize zonekeeping

 *

 * Initialize zonekeeping.

 */

void zone_init(void)

{

    spinlock_initialize(&zone_head_lock);

    list_initialize(&zone_head);

}

/** Create frame zone

 *

 * Create new frame zone.

 *

 * @param start Physical address of the first frame within the zone.

 * @param size Size of the zone. Must be a multiple of FRAME_SIZE.

 * @param flags Zone flags.

 *

 * @return Initialized zone.

 */

zone_t *zone_create(__address start, size_t size, int flags)

{

    zone_t *z;

    count_t cnt;

    int i;

    __u8 max_order;

    ASSERT(start % FRAME_SIZE == 0);

    ASSERT(size % FRAME_SIZE == 0);

    cnt = size / FRAME_SIZE;

    z = (zone_t *) early_malloc(sizeof(zone_t));

    if (z) {

        link_initialize(&z->link);

        spinlock_initialize(&z->lock);

        z->base = start;

        z->flags = flags;

        z->free_count = cnt;

        list_initialize(&z->free_head);

        z->busy_count = 0;

        z->frames = (frame_t *) early_malloc(cnt * sizeof(frame_t));

        if (!z->frames) {

            early_free(z);

            return NULL;

        }

        for (i = 0; i<cnt; i++) {

            frame_initialize(&z->frames[i], z);

            list_append(&z->frames[i].link, &z->free_head);

        }

        /*

         * Create buddy system for the zone

         */

        for (max_order = 0; cnt >> max_order; max_order++);

        z->buddy_system = buddy_system_create(max_order, &zone_buddy_system_operations);

    }

    return z;

}

/** Attach frame zone

 *

 * Attach frame zone to zone list.

 *

 * @param zone Zone to be attached.

 */

void zone_attach(zone_t *zone)

{

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&zone_head_lock);

    list_append(&zone->link, &zone_head);

    spinlock_unlock(&zone_head_lock);

    interrupts_restore(ipl);

}

/** Initialize frame structure

 *

 * Initialize frame structure.

 *

 * @param frame Frame structure to be initialized.

 * @param zone Host frame zone.

 */

void frame_initialize(frame_t *frame, zone_t *zone)

{

    frame->refcount = 0;

    link_initialize(&frame->link);

}

/*

 * buddy system functions (under construction)

 *

 */

/** Allocate 2^order frames

 *

 */

__address zone_buddy_frame_alloc(int flags, __u8 order) {

    ipl_t ipl;

    link_t *cur, *tmp;

    zone_t *z;

    zone_t *zone = NULL;

    frame_t *frame = NULL;

    __address v;

loop:

    ipl = interrupts_disable();

    spinlock_lock(&zone_head_lock);

    /*

     * First, find suitable frame zone.

     */

    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {

        z = list_get_instance(cur, zone_t, link);

        spinlock_lock(&z->lock);

        /*

         * Check if the zone has 2^order frames area available

         * TODO: Must check if buddy system has at least block in order >= given order

         */

        if (z->free_count == (1 >> order)) {

            zone = z;

            break;

        }

        spinlock_unlock(&z->lock);

    }

    if (!zone) {

        if (flags & FRAME_PANIC)

            panic("Can't allocate frame.\n");

        /*

         * TODO: Sleep until frames are available again.

         */

        spinlock_unlock(&zone_head_lock);

        interrupts_restore(ipl);

        panic("Sleep not implemented.\n");

        goto loop;

    }

    /* Allocate frames from zone buddy system */

    cur = buddy_system_alloc(zone->buddy_system, order);

    /* frame will be actually a first frame of the block */

    frame = list_get_instance(cur, frame_t, buddy_link);

    /* get frame address */

    v = FRAME2ADDR(zone, frame);

    if (flags & FRAME_KA)

        v = PA2KA(v);

    spinlock_unlock(&zone->lock);

    spinlock_unlock(&zone_head_lock);

    interrupts_restore(ipl);

    return v;

}

/** Free frame(s)

 *

 * @param addr Address of the frame(s) to be freed. It must be a multiple of FRAME_SIZE.

 */

void zone_buddy_frame_free(__address addr)

{

    ipl_t ipl;

    link_t *cur;

    zone_t *z;

    zone_t *zone = NULL;

    frame_t *frame;

    ASSERT(addr % FRAME_SIZE == 0);

    ipl = interrupts_disable();

    spinlock_lock(&zone_head_lock);

    /*

     * First, find host frame zone for addr.

     */

    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {

        z = list_get_instance(cur, zone_t, link);

        spinlock_lock(&z->lock);

        if (IS_KA(addr))

            addr = KA2PA(addr);

        /*

         * Check if addr belongs to z.

         */

        if ((addr >= z->base) && (addr <= z->base + (z->free_count + z->busy_count) * FRAME_SIZE)) {

            zone = z;

            break;

        }

        spinlock_unlock(&z->lock);

    }

    ASSERT(zone != NULL);

    frame = ADDR2FRAME(zone, addr);

    ASSERT(frame->refcount);

    if (!--frame->refcount) {

        buddy_system_free(zone->buddy_system, &frame->buddy_link);

    }

    spinlock_unlock(&zone->lock);  

    spinlock_unlock(&zone_head_lock);

    interrupts_restore(ipl);

}

/** Guess zone by frame instance address

 *

 * @param frame Frame

 *

 * @return Zone of given frame

 */

zone_t * get_zone_by_frame(frame_t * frame) {

    link_t * cur;

    zone_t * zone, *z;

    ASSERT(frame);

    /*

     * First, find host frame zone for addr.

     */

    for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {

        z = list_get_instance(cur, zone_t, link);

        spinlock_lock(&z->lock);

        /*

         * Check if frame address belongs to z.

         */

        if ((frame >= z->frames) && (frame <= z->frames + (z->free_count + z->busy_count))) {

            zone = z;

            break;

        }

        spinlock_unlock(&z->lock);

    }

    ASSERT(zone);

    return zone;

}

/** Buddy system find_buddy implementation

 * @param block Block for which buddy should be found

 *

 * @return Buddy for given block if found

 */

link_t * zone_buddy_find_buddy(link_t * block) {

    frame_t * frame, * f;

    zone_t * zone;

    link_t * cur;

    bool is_left, is_right;

    frame = list_get_instance(block, frame_t, buddy_link);

    zone = get_zone_by_frame(frame);

    /*

     * (FRAME_INDEX % 2^(ORDER+1)) == 0 ===> LEFT BUDDY

     * (FRAME_INDEX % 2^(ORDER+1)) == 2^(ORDER) ===> RIGHT BUDDY

     */

    is_left = IS_BUDDY_LEFT_BLOCK(zone, frame);

    is_right = IS_BUDDY_RIGHT_BLOCK(zone, frame);

    ASSERT((is_left || is_right) && (!is_left || !is_right));

    for (cur = &zone->buddy_system->order[frame->buddy_order]; cur; cur = cur->next) {

        f = list_get_instance(cur, frame_t, buddy_link);

        ASSERT(f->buddy_order == frame->buddy_order);

        /*

         * if found frame is coherent with our frame from the left

         */

        if ((FRAME_INDEX(zone, f) + 1 >> frame->buddy_order == FRAME_INDEX(zone, frame)) && is_right) {

            return cur;

        }

        /*

         * if found frame is coherent with our frame from the right

         */

        if ((FRAME_INDEX(zone,f) - 1 >> frame->buddy_order == FRAME_INDEX(zone, frame)) && is_left) {

            return cur;

        }

    }

    return NULL;

}

/** Buddy system bisect implementation

 *

 * @param block Block to bisect

 *

 * @return right block

 */

link_t * zone_buddy_bisect(link_t * block) {

    frame_t * frame_l, * frame_r;

    zone_t * zone;

    frame_l = list_get_instance(block, frame_t, buddy_link);

    zone = get_zone_by_frame(frame_l);

    frame_r = &zone->frames[FRAME_INDEX(zone, frame_l) + 1>>(frame_l->buddy_order-1)];

    return &frame_r->buddy_link;

}

/** Buddy system coalesce implementation

 *

 * @param block_1 First block

 * @param block_2 First block's buddy

 *

 * @return Coalesced block (actually block that represents lower address)

 */

link_t * zone_buddy_coalesce(link_t * block_1, link_t * block_2) {

    frame_t * frame1, * frame2;

    zone_t * zone;

    frame1 = list_get_instance(block_1, frame_t, buddy_link);

    frame2 = list_get_instance(block_2, frame_t, buddy_link);

    zone = get_zone_by_frame(frame1);

    return FRAME_INDEX(zone, frame1) < FRAME_INDEX(zone, frame2) ? block_1 : block_2;

}

/** Buddy system set_order implementation

 * @param block Buddy system block

 * @param order Order to set

 */

void zone_buddy_set_order(link_t * block, __u8 order) {

    frame_t * frame;

    frame = list_get_instance(block, frame_t, buddy_link);

    frame->buddy_order = order;

}

/** Buddy system get_order implementation

 * @param block Buddy system block

 *

 * @return Order of block

 */

__u8 zone_buddy_get_order(link_t * block) {

    frame_t * frame;

    frame = list_get_instance(block, frame_t, buddy_link);

    return frame->buddy_order;

}